Vectors for spacing but keep your speed...

Landis

Landis

Well-Known Member
I don't have the big picture so I'm wondering....

A couple times recently I've been given "best forward speed" followed a little while later with a "turn [60-90 degrees off course] vectors for spacing". Recently I even inquired whether slowing down would help and was told to maintain my current speed.

So, what's with keeping my speed up while turning off course? If you need spacing, can't I just slow down? Or some combination? Please fill me in.
 
A restriction like that may be in order if there are 3 or more aircraft that need to be set up in trail.
 
60-90 degrees seems excessive, but usually the case in which I'll use the technique you describe is: I need 10 miles in trail and I have 7, but speeds are already matched.

If I just slow you down, the miles in trail will continue to increase beyond 10 as you transit the next sector. Slow down then speed up isn't desirable; in fact, the 7110 cautions against issuing alternating speed adjustments. Therefore a quick 30- or 40-degree vector, then back to the fix around 9.5 does the trick, speeds still matched.

Presumably you have best forward speed because you fly a relatively slower aircraft.

Just a guess.
 
This was a CRJ200, so yes, not very fast compared to the others.

Thanks for the replies, this makes a bit more sense now.
 
As already noted, if you're in a RJ2 then you're already difficult to say the least when it comes to spacing. You may be best forward but then turned because they need further spacing from you and the aircraft you're behind but the aircraft that are behind you are still on course and we're trying to keep it that way.
 
TFaudree_ERAU said:
To 95% of the pilots I know, it is. Especially in comparison to getting a tour of the countryside.
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I'll be the 5% then. If you give me "170 knots" then "max forward speed" I'm going to wonder what it is that's happening in that radar room, versus a vector for sequence.
 
I made a graphic depiction of why we sometimes do this. In Paint no less.

I'll try and find it


Also could just be that "fark that plan didnt work, you're now number 5 instead if number 1"
 
Autothrust Blue said:
I'll be the 5% then. If you give me "170 knots" then "max forward speed" I'm going to wonder what it is that's happening in that radar room, versus a vector for sequence.
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Maybe it's just us corporate guys and the propensity for the owner to come up to the cockpit or after landing ask us why we were zig zagging all over the sky. Never have I been asked why we slowed down by 40 knots; if done correctly, they can't tell.
 
TFaudree_ERAU said:
Maybe it's just us corporate guys and the propensity for the owner to come up to the cockpit or after landing ask us why we were zig zagging all over the sky. Never have I been asked why we slowed down by 40 knots; if done correctly, they can't tell.
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"Because despite having the call sign ONE PERCENT, almost all airplanes are created equally in the eyes of ATC."
 
Autothrust Blue said:
I'll be the 5% then. If you give me "170 knots" then "max forward speed" I'm going to wonder what it is that's happening in that radar room, versus a vector for sequence.
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Usually that just means that the plan changed. I try to say something along those lines so people understand.

To add to this thread, the thing about controllers is that all of us are incredibly impatient. I remember, when I was the academy someone early on said to me during a simulation as I was getting antsy that I need to get used to it because we spend our entire careers waiting to do things at the right time. Now, I'm not going to lie...I'm very young and I only recently fully certified. Having said that, I don't have the 20+ years of experience where I know that a speed will work, especially when you throw in high winds. I would probably be the guy that would turn you out even though a speed adjustment would have worked. Ask me again 10 years from now.
 
there are times where you dont have the time or the airspace for a speed to work, so you vector.....its quicker.
 
A situation where I'd assign a faster speeed then turn you out...

You are in a long line heading for an arrival gate coming from different transitions. The guy in front of you is say 10 miles from the gate fix. You are 13.5 miles and the guy behind you is 20 miles from the fix. If I slowed you down, it would force me to slap 250, or whatever speed I give you to the entire string behind you. That could be 1 plane...or 20 planes behind you.

In my situation, I assign you the speed if the guy up front then turn you to get the 1.5 miles I need then back on course. Least amount of work.

Sent from my SAMSUNG-SGH-I747 using Tapatalk 2
 
Usually I am anticipating a pilot being slow, or because I'm turning them into a headwind I need for them to have their speed up before turning back on course to match those of the aircraft in front. In any case, it is usually because there are other aircraft following just far enough behind that I can avoid turning them or applying drastic speed reductions if the aircraft I turn speeds up a bit.
 
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